[PATCH] mfd: Add support for CPLD chip on Mikrotik RB4xx boards

[Bert Vermeulen]

The SPI-connected CPLD chip controls access to the main NAND flash
chip and five LEDs.

Signed-off-by: Bert Vermeulen <bert@xxxxxxxx>
---
 arch/mips/include/asm/mach-ath79/rb4xx_cpld.h |  49 +++++
 drivers/mfd/Kconfig                           |   7 +
 drivers/mfd/Makefile                          |   1 +
 drivers/mfd/rb4xx-cpld.c                      | 279 ++++++++++++++++++++++++++
 4 files changed, 336 insertions(+)
 create mode 100644 arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
 create mode 100644 drivers/mfd/rb4xx-cpld.c

diff --git a/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h b/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
new file mode 100644
index 0000000..40c109c
--- /dev/null
+++ b/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
@@ -0,0 +1,49 @@
+/*
+ * SPI driver definitions for the CPLD chip on the Mikrotik RB4xx boards
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ *
+ * This file was based on the patches for Linux 2.6.27.39 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#define CPLD_GPIO_LED1		0
+#define CPLD_GPIO_LED2		1
+#define CPLD_GPIO_LED3		2
+#define CPLD_GPIO_LED4		3
+#define CPLD_GPIO_FAN		4
+#define CPLD_GPIO_ALE		5
+#define CPLD_GPIO_CLE		6
+#define CPLD_GPIO_nCE		7
+#define CPLD_GPIO_LED5		8
+
+#define CPLD_NUM_GPIOS		9
+
+#define CPLD_CFG_LED1		BIT(CPLD_GPIO_LED1)
+#define CPLD_CFG_LED2		BIT(CPLD_GPIO_LED2)
+#define CPLD_CFG_LED3		BIT(CPLD_GPIO_LED3)
+#define CPLD_CFG_LED4		BIT(CPLD_GPIO_LED4)
+#define CPLD_CFG_FAN		BIT(CPLD_GPIO_FAN)
+#define CPLD_CFG_ALE		BIT(CPLD_GPIO_ALE)
+#define CPLD_CFG_CLE		BIT(CPLD_GPIO_CLE)
+#define CPLD_CFG_nCE		BIT(CPLD_GPIO_nCE)
+#define CPLD_CFG_LED5		BIT(CPLD_GPIO_LED5)
+
+#define CPLD_CMD_WRITE_NAND	0x08 /* send cmd, n x send data, send idle */
+#define CPLD_CMD_WRITE_CFG	0x09 /* send cmd, n x send cfg */
+#define CPLD_CMD_READ_NAND	0x0a /* send cmd, send idle, n x read data */
+#define CPLD_CMD_READ_FAST	0x0b /* send cmd, 4 x idle, n x read data */
+#define CPLD_CMD_LED5_ON	0x0c /* send cmd */
+#define CPLD_CMD_LED5_OFF	0x0d /* send cmd */
+
+struct rb4xx_cpld_platform_data {
+	unsigned gpio_base;
+};
+
+extern int rb4xx_cpld_read(struct spi_device *spi, unsigned char *rx_buf,
+			   unsigned len);
+extern int rb4xx_cpld_write(struct spi_device *spi, const u8 *buf, int len);
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 38356e3..c4a6a4e 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -631,6 +631,13 @@ config MFD_SPMI_PMIC
 	  Say M here if you want to include support for the SPMI PMIC
 	  series as a module.  The module will be called "qcom-spmi-pmic".
 
+config MFD_RB4XX_CPLD
+	tristate "MikroTik RB4XX CPLD driver"
+	depends on ATH79 && SPI_RB4XX
+	help
+	  Driver for the CPLD chip present on MikroTik RB4xx boards.
+	  It controls CPU access to NAND flash and user LEDs.
+
 config MFD_RDC321X
 	tristate "RDC R-321x southbridge"
 	select MFD_CORE
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 19f3d74..6cc9fe3 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -155,6 +155,7 @@ obj-$(CONFIG_MFD_OMAP_USB_HOST)	+= omap-usb-host.o omap-usb-tll.o
 obj-$(CONFIG_MFD_PM8921_CORE) 	+= pm8921-core.o ssbi.o
 obj-$(CONFIG_MFD_QCOM_RPM)	+= qcom_rpm.o
 obj-$(CONFIG_MFD_SPMI_PMIC)	+= qcom-spmi-pmic.o
+obj-$(CONFIG_MFD_RB4XX_CPLD)	+= rb4xx-cpld.o
 obj-$(CONFIG_TPS65911_COMPARATOR)	+= tps65911-comparator.o
 obj-$(CONFIG_MFD_TPS65090)	+= tps65090.o
 obj-$(CONFIG_MFD_AAT2870_CORE)	+= aat2870-core.o
diff --git a/drivers/mfd/rb4xx-cpld.c b/drivers/mfd/rb4xx-cpld.c
new file mode 100644
index 0000000..0f8de62
--- /dev/null
+++ b/drivers/mfd/rb4xx-cpld.c
@@ -0,0 +1,279 @@
+/*
+ * SPI driver for the CPLD chip on the Mikrotik RB4xx boards
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ *
+ * This file was based on the patches for Linux 2.6.27.39 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/bitops.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+
+#include <asm/mach-ath79/rb4xx_cpld.h>
+
+struct rb4xx_cpld {
+	struct spi_device *spi;
+	struct mutex lock;
+	struct gpio_chip chip;
+	unsigned int config;
+};
+
+static inline struct rb4xx_cpld *gpio_to_cpld(struct gpio_chip *chip)
+{
+	return container_of(chip, struct rb4xx_cpld, chip);
+}
+
+static int rb4xx_cpld_write_cmd(struct rb4xx_cpld *cpld, unsigned char cmd)
+{
+	struct spi_transfer t[1];
+	struct spi_message m;
+	unsigned char tx_buf[1];
+	int err;
+
+	spi_message_init(&m);
+	memset(&t, 0, sizeof(t));
+
+	t[0].tx_buf = tx_buf;
+	t[0].len = sizeof(tx_buf);
+	spi_message_add_tail(&t[0], &m);
+
+	tx_buf[0] = cmd;
+
+	err = spi_sync(cpld->spi, &m);
+	return err;
+}
+
+static int rb4xx_cpld_write_cfg(struct rb4xx_cpld *cpld, unsigned char config)
+{
+	struct spi_transfer t[1];
+	struct spi_message m;
+	unsigned char cmd[2];
+	int err;
+
+	spi_message_init(&m);
+	memset(&t, 0, sizeof(t));
+
+	t[0].tx_buf = cmd;
+	t[0].len = sizeof(cmd);
+	spi_message_add_tail(&t[0], &m);
+
+	cmd[0] = CPLD_CMD_WRITE_CFG;
+	cmd[1] = config;
+
+	err = spi_sync(cpld->spi, &m);
+	return err;
+}
+
+static int rb4xx_cpld_change_cfg(struct rb4xx_cpld *cpld, u32 mask, u32 value)
+{
+	unsigned int config;
+	int err;
+
+	config = cpld->config & ~mask;
+	config |= value;
+
+	if ((cpld->config ^ config) & 0xff) {
+		err = rb4xx_cpld_write_cfg(cpld, config);
+		if (err)
+			return err;
+	}
+
+	if ((cpld->config ^ config) & CPLD_CFG_LED5) {
+		err = rb4xx_cpld_write_cmd(cpld, (value) ? CPLD_CMD_LED5_ON :
+							   CPLD_CMD_LED5_OFF);
+		if (err)
+			return err;
+	}
+
+	cpld->config = config;
+	return 0;
+}
+
+int rb4xx_cpld_read(struct spi_device *spi, unsigned char *rx_buf, unsigned len)
+{
+	struct spi_message m;
+	static const unsigned char cmd[2] = { CPLD_CMD_READ_NAND, 0 };
+	struct spi_transfer t[2] = {
+		{
+			.tx_buf = &cmd,
+			.len = 2,
+		}, {
+			.rx_buf = rx_buf,
+			.len = len,
+		},
+	};
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+	return spi_sync(spi, &m);
+}
+EXPORT_SYMBOL_GPL(rb4xx_cpld_read);
+
+/* The cs_change flag indicates to the spi-rb4xx driver to use "fast mode". */
+int rb4xx_cpld_write(struct spi_device *spi, const u8 *buf, int len)
+{
+	struct spi_message m;
+	static const unsigned char cmd = CPLD_CMD_WRITE_NAND;
+	static const unsigned char dummy = 0x00;
+	struct spi_transfer t[3] = {
+		{
+			.tx_buf = &cmd,
+			.len = 1,
+		}, {
+			.tx_buf = buf,
+			.len = len,
+			.cs_change = 1,
+		}, {
+			.tx_buf = &dummy,
+			.len = 1,
+			.cs_change = 1,
+		},
+	};
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+	spi_message_add_tail(&t[2], &m);
+	return spi_sync(spi, &m);
+}
+EXPORT_SYMBOL_GPL(rb4xx_cpld_write);
+
+static int rb4xx_cpld_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+	int ret;
+
+	mutex_lock(&cpld->lock);
+	ret = (cpld->config >> offset) & 1;
+	mutex_unlock(&cpld->lock);
+
+	return ret;
+}
+
+static void rb4xx_cpld_gpio_set(struct gpio_chip *chip,
+				unsigned offset, int value)
+{
+	struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+
+	mutex_lock(&cpld->lock);
+	rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
+	mutex_unlock(&cpld->lock);
+}
+
+static int rb4xx_cpld_gpio_direction_input(struct gpio_chip *chip,
+					   unsigned offset)
+{
+	return -EOPNOTSUPP;
+}
+
+static int rb4xx_cpld_gpio_direction_output(struct gpio_chip *chip,
+					    unsigned offset, int value)
+{
+	struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+	int ret;
+
+	mutex_lock(&cpld->lock);
+	ret = rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
+	mutex_unlock(&cpld->lock);
+
+	return ret;
+}
+
+static int rb4xx_cpld_gpio_init(struct rb4xx_cpld *cpld, unsigned int base)
+{
+	int err;
+
+	cpld->chip.label = "rb4xx-cpld";
+	cpld->chip.base = base;
+	cpld->chip.ngpio = CPLD_NUM_GPIOS;
+	cpld->chip.can_sleep = 1;
+	cpld->chip.dev = &cpld->spi->dev;
+	cpld->chip.owner = THIS_MODULE;
+	cpld->chip.get = rb4xx_cpld_gpio_get;
+	cpld->chip.set = rb4xx_cpld_gpio_set;
+	cpld->chip.direction_input = rb4xx_cpld_gpio_direction_input;
+	cpld->chip.direction_output = rb4xx_cpld_gpio_direction_output;
+
+	err = gpiochip_add(&cpld->chip);
+	if (err)
+		dev_err(&cpld->spi->dev, "adding GPIO chip failed, error %d\n",
+			err);
+
+	return err;
+}
+
+static int rb4xx_cpld_probe(struct spi_device *spi)
+{
+	struct rb4xx_cpld *cpld;
+	struct rb4xx_cpld_platform_data *pdata;
+	int err;
+
+	pdata = spi->dev.platform_data;
+	if (!pdata) {
+		dev_dbg(&spi->dev, "no platform data\n");
+		return -EINVAL;
+	}
+
+	cpld = devm_kzalloc(&spi->dev, sizeof(*cpld), GFP_KERNEL);
+	if (!cpld)
+		return -ENOMEM;
+
+	mutex_init(&cpld->lock);
+	cpld->spi = spi_dev_get(spi);
+	dev_set_drvdata(&spi->dev, cpld);
+
+	spi->mode = SPI_MODE_0;
+	err = spi_setup(spi);
+	if (err) {
+		dev_err(&spi->dev, "SPI setup failed, error %d\n", err);
+		return err;
+	}
+
+	err = rb4xx_cpld_gpio_init(cpld, pdata->gpio_base);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int rb4xx_cpld_remove(struct spi_device *spi)
+{
+	struct rb4xx_cpld_platform_data *pdata;
+	struct rb4xx_cpld *cpld;
+
+	pdata = spi->dev.platform_data;
+	cpld = dev_get_drvdata(&spi->dev);
+	mutex_destroy(&cpld->lock);
+
+	return 0;
+}
+
+static struct spi_driver rb4xx_cpld_driver = {
+	.probe = rb4xx_cpld_probe,
+	.remove = rb4xx_cpld_remove,
+	.driver = {
+		.name = "rb4xx-cpld",
+		.bus = &spi_bus_type,
+		.owner = THIS_MODULE,
+	},
+};
+
+module_spi_driver(rb4xx_cpld_driver);
+
+MODULE_DESCRIPTION("RB4xx CPLD driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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